Decrease rate of spring.

Ironjunk

Well-Known Member
I bought a rear coil shock for my ebike after the air spring blew out. It's good enough to get by but wish it were softer. The coil itself is very short and is about 3/4 inch shorter than the longest collar setting. If I heat and stretch the coil and lengthen it will it give me a softer ride?
 
Sir, set the torch down and walk away. The ideal route would be to use one of the online rate calculators to find your true target spring rate. Then buy an adjustable Sprindex brand spring specific for your shock dimensions that covers that value that way you still have some adjustment.
 
I bought a rear coil shock for my ebike after the air spring blew out. It's good enough to get by but wish it were softer. The coil itself is very short and is about 3/4 inch shorter than the longest collar setting. If I heat and stretch the coil and lengthen it will it give me a softer ride?
You need to purchase the correct spring rate for your weight. But, I just have to ask. How exactly would you plan to heat up and stretch that spring?
 
Which shock did you purchase?

This is a good place to start: TF Tuned

You'll need to consider rate, length and stroke to get the correct one.

My go-to springs: MRP
 
Reduce pre load as much as possible. Take all free play out then 1/2 turn to keep spring seated . Open all adjustments you'd be surprised by a slightly slow rebound can cause an extremely stiff feeling shock
 
You need to purchase the correct spring rate for your weight. But, I just have to ask. How exactly would you plan to heat up and stretch that spring?
I can probably think of like 6 different ways once i start browsing the shop. But off the top of my head. Wedging stuff in the coils then heating it. Hanging weights from it, 2 gear pullers. Put it around and pipe and use the gear pullers on the ends of the pipe and heat it up? Weld crap to the ends then just figure it out as i go. The iron shiek is dead i would have asked him to just pull it apart.


It's this shock. I just needed something to get buy and i guessed it would work. I'd rather use what i have rather than buying new things and throwing stuff out.

Reduce pre load as much as possible. Take all free play out then 1/2 turn to keep spring seated . Open all adjustments you'd be surprised by a slightly slow rebound can cause an extremely stiff feeling shock
With the spring barely seated it's still too stiff. My rebound is fully open


I suppose this is more of a physics question. If you lengthen a shock with a certain amount of coils and diameter, does it get softer?
 
Last edited:
I can probably think of like 6 different ways once i start browsing the shop.


It's this shock. I just needed something to get buy and i guessed it would work. I'd rather use what i have rather than buying new things and throwing stuff out.


With the spring barely seated it's still too stiff.

more turns on the coil decreases the rate so does diameter i guess.

I suppose this is more of a physics question. If you lengthen a shock with a certain amount of coils, does it get softer?
If you could actually do this, wouldn't the diameter shrink as you stretched it out?
 
  • Like
Reactions: rlb
I can probably think of like 6 different ways once i start browsing the shop. But off the top of my head. Wedging stuff in the coils then heating it. Hanging weights from it, 2 gear pullers. Put it around and pipe and use the gear pullers on the ends of the pipe and heat it up? Weld crap to the ends then just figure it out as i go. The iron shiek is dead i would have asked him to just pull it apart.


It's this shock. I just needed something to get buy and i guessed it would work. I'd rather use what i have rather than buying new things and throwing stuff out.


With the spring barely seated it's still too stiff. My rebound is fully open


I suppose this is more of a physics question. If you lengthen a shock with a certain amount of coils and diameter, does it get softer?

Have these in my desk drawer for reference. Refer to the chart below. Both the same length, but different spring rates. As @Ryan.P mentioned, just buy the correct spring rate.

20241025_112124.jpg


1729869885187.png
 
Thanks guy i'm trying to get the bike ready for the martys race. The coil is 30mm-1 3/16" ID and 115mm- 4 3/8" length
 
Last edited:
I can probably think of like 6 different ways once i start browsing the shop. But off the top of my head. Wedging stuff in the coils then heating it. Hanging weights from it, 2 gear pullers. Put it around and pipe and use the gear pullers on the ends of the pipe and heat it up? Weld crap to the ends then just figure it out as i go. The iron shiek is dead i would have asked him to just pull it apart.


It's this shock. I just needed something to get buy and i guessed it would work. I'd rather use what i have rather than buying new things and throwing stuff out.


With the spring barely seated it's still too stiff. My rebound is fully open


I suppose this is more of a physics question. If you lengthen a shock with a certain amount of coils and diameter, does it get softer?

the spring rate is independent of spring length, up until it deforms or bottoms.
that doesn't mean a longer spring doesn't act differently with the same forces.

consider two [identical] spring scales, hang one from the other, zero them.
hang a 5lb weight on it. both scales will read 5lbs - so the displacement of the weight is double that if you only hung it from 1 scale.

wait, did I just half the rate by doubling the length?
@shrpshtr325 ?
 
Last edited:
Back
Top Bottom